Well it is just a matter of time till new comers will join Bitcoin after they start learning more and more from it.
Social Media is a big part if everything for that and spreading the word to your family, friends and those who don't have a clue what Bitcoin or any crypto currency really is.

In case of those without internet / electricity i am sure there will be some more new ways for them.
Who knows if those who have a bank account will be informed about bitcoin and cryptocurrency system from their banks instead.
Also banks will possible be able to issue some Crypto cards where you could use your fiat as a crypto currency.